diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/RuleSet.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/RuleSet.java
index 39b0de33..1669b760 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/RuleSet.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/RuleSet.java
@@ -439,7 +439,7 @@ public class RuleSet implements IRuleSet{
 		if(!(rhsType instanceof ReferenceType) && !(rhsType instanceof PlaceholderType))
 			return false;
 		
-		return fc.greater(lhsType, new HashSet<>()).contains(rhsType);
+		return fc.greater(lhsType, new HashSet<>(), pair.getLocation()).contains(rhsType);
 	}
 
 	@Override
diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/interfaces/IFiniteClosure.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/interfaces/IFiniteClosure.java
index 557b664a..5868f0ea 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/interfaces/IFiniteClosure.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/interfaces/IFiniteClosure.java
@@ -10,6 +10,7 @@ import de.dhbwstuttgart.typeinference.unify.model.PlaceholderType;
 import de.dhbwstuttgart.typeinference.unify.model.ReferenceType;
 import de.dhbwstuttgart.typeinference.unify.model.SuperType;
 import de.dhbwstuttgart.typeinference.unify.model.UnifyType;
+import org.antlr.v4.runtime.Token;
 
 /**
  * 
@@ -22,13 +23,19 @@ public interface IFiniteClosure {
 	 * Returns all types of the finite closure that are subtypes of the argument.
 	 * @return The set of subtypes of the argument.
 	 */
-	public Set<UnifyType> smaller(UnifyType type, Set<UnifyType> fBounded);
+	public Set<UnifyType> smaller(UnifyType type, Set<UnifyType> fBounded, Token position);
+	public default Set<UnifyType> smaller(UnifyType type, Set<UnifyType> fBounded) {
+		return this.smaller(type, fBounded, null);
+	}
 	
 	/**
 	 * Returns all types of the finite closure that are supertypes of the argument.
 	 * @return The set of supertypes of the argument.
 	 */
-	public Set<UnifyType> greater(UnifyType type, Set<UnifyType> fBounded);
+	public Set<UnifyType> greater(UnifyType type, Set<UnifyType> fBounded, Token position);
+	public default Set<UnifyType> greater(UnifyType type, Set<UnifyType> fBounded) {
+		return this.greater(type, fBounded, null);
+	}
 
 	/**
 	 * Wo passt Type rein?
diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java
index 55340fdc..f5671686 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java
@@ -27,6 +27,7 @@ import de.dhbwstuttgart.typeinference.unify.TypeUnifyTask;
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
 import de.dhbwstuttgart.typeinference.unify.interfaces.IUnify;
 import de.dhbwstuttgart.util.Pair;
+import org.antlr.v4.runtime.Token;
 
 /**
  * The finite closure for the type unification
@@ -145,7 +146,7 @@ implements IFiniteClosure  {
 	 * @return The set of subtypes of the argument.
 	 */
 	@Override
-	public Set<UnifyType> smaller(UnifyType type, Set<UnifyType> fBounded) {
+	public Set<UnifyType> smaller(UnifyType type, Set<UnifyType> fBounded, Token position) {
 		
 		Set<UnifyType> ret;
 		if ((ret = smallerHash.get(new hashKeyType(type))) != null) {
@@ -260,8 +261,7 @@ implements IFiniteClosure  {
 	 */
 	@Override
 	//Eingefuegt PL 2018-05-24 F-Bounded Problematik
-	public Set<UnifyType> greater(UnifyType type, Set<UnifyType> fBounded) {
-		
+	public Set<UnifyType> greater(UnifyType type, Set<UnifyType> fBounded, Token location) {
 		Set<UnifyType> ret;
 		if ((ret = greaterHash.get(new hashKeyType(type))) != null) {
 			//System.out.println(greaterHash);
@@ -302,7 +302,7 @@ implements IFiniteClosure  {
 			
 			//PL 18-04-05 Unifier durch Matcher ersetzt ANFANG
 			ArrayList<UnifyPair> termList= new ArrayList<UnifyPair>();
-			termList.add(new UnifyPair(theta1,type, PairOperator.EQUALSDOT));
+			termList.add(new UnifyPair(theta1,type, PairOperator.EQUALSDOT, location));
 			Optional<Unifier> optSigma = match.match(termList);
 			//PL 18-04-05 Unifier durch Matcher ersetzt ENDE
 			if(!optSigma.isPresent()) {
@@ -344,7 +344,7 @@ implements IFiniteClosure  {
 					BiFunction<Boolean,UnifyType,Boolean> f = (x,y) -> 
 					{
 						ArrayList<UnifyPair> termList = new ArrayList<UnifyPair>();
-					    termList.add(new UnifyPair(y,t.getTypeParams().get(i_ef), PairOperator.EQUALSDOT));
+					    termList.add(new UnifyPair(y,t.getTypeParams().get(i_ef), PairOperator.EQUALSDOT, location));
 					    return ((match.match(termList).isPresent()) || x);
 					};
 					//if (parai.getName().equals("java.lang.Integer")) {
diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/model/Unifier.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/model/Unifier.java
index 8cfac643..db050c03 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/model/Unifier.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/model/Unifier.java
@@ -102,7 +102,7 @@ public class Unifier implements Function<UnifyType, UnifyType>, Iterable<Entry<P
 			}
 			return new UnifyPair(newLhs, newRhs, p.getPairOp(), suniUnifyPair, p);
 		}
-		return new UnifyPair(newLhs, newRhs, p.getPairOp(), p.getSubstitution(), p.getBasePair(), p.getfBounded());
+		return new UnifyPair(newLhs, newRhs, p.getPairOp(), p.getSubstitution(), p.getBasePair(), p.getfBounded(), p.getLocation());
 	}
 	
 	/**
diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/model/UnifyPair.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/model/UnifyPair.java
index ab2be5ec..34069374 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/model/UnifyPair.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/model/UnifyPair.java
@@ -1,6 +1,7 @@
 package de.dhbwstuttgart.typeinference.unify.model;
 
 import com.google.common.collect.ObjectArrays;
+import de.dhbwstuttgart.syntaxtree.type.TypePlaceholder;
 import org.antlr.v4.runtime.Token;
 
 import java.util.ArrayList;
@@ -79,26 +80,28 @@ public class UnifyPair {
 	}
 	
 	public UnifyPair(UnifyType lhs, UnifyType rhs, PairOperator op, Set<UnifyPair> uni, UnifyPair base) {
+		this(lhs, rhs, op, uni, base, null);
+	}
+
+	public UnifyPair(UnifyType lhs, UnifyType rhs, PairOperator op, Set<UnifyPair> uni, UnifyPair base, Set<UnifyType> fBounded) {
+		this(lhs, rhs, op, uni, base, fBounded, null);
+	}
+
+	public UnifyPair(UnifyType lhs, UnifyType rhs, PairOperator op, Set<UnifyPair> uni, UnifyPair base, Set<UnifyType> fBounded, Token location) {
 		this.lhs = lhs;
 		this.rhs = rhs;
 		pairOp = op;
 		substitution = uni;
 		basePair = base;
-		
-		
+		this.location = location;
+
 		// Caching hashcode
 		hashCode = 17 + 31 * lhs.hashCode() + 31 * rhs.hashCode() + 31 * pairOp.hashCode();
-	}	
-	
-	public UnifyPair(UnifyType lhs, UnifyType rhs, PairOperator op, Set<UnifyPair> uni, UnifyPair base, Set<UnifyType> fBounded) {
-		this(lhs, rhs, op, uni, base);
-		
-		this.fBounded = fBounded;
 	}
 
 	public Token getLocation() {
 		if (location != null) return location;
-		else if (basePair != null) return basePair.getLocation();;
+		else if (basePair != null) return basePair.getLocation();
 		return null;
 	}